Process for the preparation of aliphatic dinitriles

ABSTRACT

1,4-Dicyanobutene and adiponitrile are made by heating acrylonitrile with a ruthenium catalyst in the presence of hydrogen.

United States Patent Chabardes et al. 14 1 June 20, 1972 PROCESS FOR THEPREPARATION OF [56] References Cited ALIPHATIC DINITRILES UNITED STATESPATENTS [72] Inventors: Pierre Chabardes; Pierre Gandilhon- CharlesGrard, a" of Lyon; Michel 2,999,107 Lmdsey, J1. CI 81 Birgnais, a ofFrance 3,013,066 12/1961 Alderson ..260/486 3,322,815 5/1967 Fcldman etal. 1 ..260/465.5 Asslgneel khone-Poulenc -A-, Pans, France 3,350,439/1967 Feldman et a1. ..260 465.5 [22] Filed March FOREIGN PATENTS ORAPPLICATIONS [21] 535322 1,411,003 10/1965 France ..260/465.8

[] Foreign Application Priority Data Primary Examiner-Joseph P. BrustMarch 18, 1965 France ..659738 Msher July 19, 1965 France.... ..6525lDec. 2, 1965 France ..6540725 [57] ABSTRACT 1,4-Dicyanobutene andadiponitrile are made by heating [52] U.S.Cl. ..Z60/465.8 D,260/464,260/465.l acfylonitfile with a rutmmium alalyst in the presenceof 51 161.01 ..C07c 121/26 hydrogen [58] Field ofSearch 5 Claims, NoDrawings PROCESS FOR THE PREPARATION OF ALIPHATIC DINITRILES The presentinvention relates to the preparation of 1,4- dicyanobutenes and/oradiponitrile by the dimerization of acrylonitrile.

It is known that heating a mixture of acrylonitrile and tertiaryphosphines yields 2,4-dicyanobutene-l (French specification No.1,366,081) whose hydrogenation yields 2-methylglutaronitrile. It is alsoknown that heating a mixture of acrylonitrile, a tertiary phosphine anda proton donating agent such as water, or an alcohol (FrenchSpecification No. 1,385,883) gives a mixture of straight-chain orbranched monoethylenic dinitriles having six carbon atoms; however, theamount of straight chain dimer is always low. It is also known todimerize acrylonitrile to give 1,2-dicyanocyclobutane the hydrogenolysisof which gives adiponitrile, but this method requires the use of hightemperatures and pressures. It has also been suggested to convertacrylonitrile directly to adiponitrile by hydrodimerization methodswhich resort to the use of nascent hydrogen. Thus, according to U.S.Pat. No..

3,133,956, adiponitrile may be obtained by reacting acrylonitrile inaqueous solution with a dispersion of finely divided sodium in an inertorganic solvent. The yields of adiponitrile are always low, bothrelative to the acrylonitrile and relative to the metallic sodiumconsumed. Equally, treating acrylonitrile with magnesium in a primaryaliphatic monoalcohol, in the presence of mercuric chloride as anactivator, according to U.S. Pat. No. 2,439,308, only gives low yieldsof adiponitrile.

French specification No. 1,229,702 describes a method of dimerizingalpha-olefines as well as alpha-olefinic functional derivatives, byheating them under pressure in the presence of a salt of a noble metalof Group VIII of the Periodic Table. Though it is true that acrylicesters may be dimerized by this method, it has been observed that themethod does not permit the dimerization of acrylonitrile.

A process for the preparation of l,4-dicyanobutenes and/or adiponitrilehas now been found, starting from acrylonitrile and taking placedirectly in a single stage, this method comprising heating acrylonitrileunder a hydrogen pressure of l to 50 bars in the presence of, ascatalyst, an organic or inorganic ruthenium derivative. There areobtained by this process straight chain dinitriles to the substantialexclusion of branched or cyclic products such as methylglutaronitrilesor 1,2-dicyanocyclobutane.

The predominant formation of 1,4-dicyanobutenes or of adiponitrile islinked to the working conditions and to the ruthenium catalyst which isused. A judicious choice of conditions allows the reaction to bedirected towards the predominant formation of one or other of theseproducts, and also enables the formation of propionitrile, which is aby-product resulting from the hydrogenation of acrylonitrile, to bereduced.

The catalysts which may be used according to the method of the inventionare inorganic or organic ruthenium derivatives, preferably salts ofmineral or organic acids. Examples of suitable catalysts are halides,thiocyanates, salts of oxygen-containing mineral acids such as thesulphates, nitrates, oxyhalides and hydroxyhalides, and salts of organicaliphatic, cycloaliphatic or aromatic acids such as the acetate,oxalate, stearate or naphthenate. The alcoholates and phenates may alsobe used. As other inorganic or organic ruthenium com pounds there may benamed the alkali and alkaline earth ruthenates, mixed salts of rutheniumand an alkali metal, such as the halogenoruthenates of sodium orpotassium, and halogenated or nitrosylated or aminated derivatives suchas nitrosochlororuthenium or trichlororuthenium hexamine. Chelates suchas the acetylacetonates, optionally substituted by, for example,aliphatic or cycloaliphatic groups or by halogen atoms, such as3-bromo-2,4-pentadionatoruthenium (111) or 1,1,l-trifluoro2,4-pentadionatoruthenium (Ill), glyoximates, quinolinates,salicylaldehydates, and derivatives of ethylene diamine, a, a'-dipyridyland o-phenanthroline are also suitable. Other catalysts which areparticularly suitable are the complexes which ruthenium derivatives formwith electron donating agents. Such complexes are, for example, obtainedby using, as the ruthenium derivatives, halogenated, carbonylated ornitrosylated ruthenium derivatives, and as the electron donating agents,substances having lone electron pairs such as the phosphines, arsines,stibines, amines or substances capable of forming structures having loneelectron pairs and thus also able to act as electron donors. It is thuspossible to use complexes formed with the electron donating agentsspecifically named in French specification No. 1,337,558. Complexeswhich are suitable may be obtained from the reaction of rutheniumcompounds, especially the halides and hydridohalides, with aliphatic orcycloaliphatic monoolefines and diolefines, such as for examplebutadiene, isoprene or cyclooctadiene, with activated olefines such asacrylic or methacrylic derivatives like acrolein, methacrolein oracrylamide, with saturated or unsaturated aliphatic, cycloaliphatic oraromatic nitriles such as acetonitrile, propionitrile, acrylonitrile,methacrylonitrile, cyanocyclohexane, benzonitrile, or toluonitrile, andwith saturated or unsaturated dinitriles such as malonitrile,succinonitrile, adiponitrile, dicyanobutanes, dicyanocyclobutanes,dicyanobutenes, and aliphatic or aromatic isonitriles. Such complexesmay be produced by heating a ruthenium halide withan electron donor,optionally in the presence of a solvent which may itself participate inthe preparation of the complex.

An amount of catalyst corresponding to an amount of metallic rutheniumranging from 0.04 to 1.2 percent by weight of the acrylonitrile which itis intended to treat is generally suitable for the implementation of themethod of the invention. However these limits are not rigid and in thecase of particularly reactive ruthenium derivatives such as rutheniumtrichloride or ruthenium acetylacetonate smaller amounts such as forexample 0.01 percent or even 0.001 percent of ruthenium may be used. Thecatalysts may be used in the solid state, in a subdivided form, insuspension or in solution in water or in an organic solvent which isinert under the conditions of the reaction. The catalysts do not change,or change only very slightly, during the course of the reaction and theymay be reused a number of times without it being necessary to regeneratethem each time.

It is essential for the reaction to be carried out in the presence ofhydrogen, which may be introduced into the reaction zone all at once orin batches, or even continuously so as to maintain a constant hydrogenpressure. The pressure and temperature may vary between certain limits,most commonly l to 50 bars pressure and 50 to 150 C. temperature. It isnot advantageous to work outside these limits. Below the lower limits,the reaction takes place slowly, whereas above the upper limits aconsiderable amount of propionitrile is formed by the directhydrogenation of acrylonitrile, to the detriment of the yield of thedesired products. The most advantageous working conditions are in therange of 5 to 40 bars and to C. Depending on the working conditions,there are obtained 1,4-dicyanobutenes or adiponitrile or their mixtures.ln order to obtain 1,4-dicyanobutenes to the exclusion of adiponitrile,or at least to produce as little adiponitrile as possible, it isadvantageous to work at the lower hydrogen pressure. It is also possibleto limit the reaction to the formation of 1,4-dicyanobutenes by loweringthe reaction temperature or reducing the duration of heating. Finally,the reaction may also be directed towards the formation ofdicyanobutenes by choosing a less active catalyst, or by using a moreactive catalyst but at a low degree of conversion, or by working in adilute medium.

In order to obtain exclusively, or almost exclusively, adiponitrile itis conversely advisable to use hydrogen at a higher pressure. It iseither possible to work with a single introduction of hydrogen if underthe working conditions (volume of apparatus and initial pressure) thepressure, while diminishing, nevertheless remains always sufi'rcientlyhigh to give the desired result, or preferably to work with thereplacement, or continuous feed, of hydrogen so as to keep the hydrogenpressure constant at a suitable higher value. For a given pressure, thereaction may also be directed towards the predominant formation ofadiponitrile by again using the effect of temperature, or the nature ofthe catalyst and of its amount in the reaction mixture. Increasing theproportion of catalyst has the effect of directing the reaction towardsthe formation of adiponitrile. It is thus seen that both for theformation of 1,4-dicyanobutenes and for the formation of adiponitrilethere is a close relationship between the working conditions and it ispossible that in certain cases one obtains neither one or the other ofthese dinitriles but mixtures of both. These mixtures may be subjectedto catalytic hydrogenation in order to convert them quantitatively toadiponitrile, as may also be done for the 1,4-dicyanobutenes alone.

The acrylonitrile used in the reaction may either be commerciallyavailable acrylonitrile or freshly distilled and unstabilizedacrylonitrile, or also distilled acrylonitrile to which very smallamounts of stabilizers such as hydroquinone, p-tertiary butylpyrocatechol, p-nitrosodimethylaniline or ammonia are added.

The reaction may be carried out in the presence or absence of anauxiliary diluent, which is liquid and inert under the workingconditions. Amongst these diluents there may be named water, alcoholssuch as methanol or ethanol, glycols, glycol ethers such asmethoxyethanolordiethyleneglycol dimethyl ether, cyclic ethers such asdioxane and tetrahydrofuran, aliphatic, cycloaliphatic or aromatichydrocarbons such as benzene or cyclohexane, nitriles such asacetonitrile or propionitrile, nitro-derivatives or amides.

When the reaction is ended the unconverted acrylonitrile may be isolatedby distilling the reaction mixture at 80 to 100 C at normal pressure, asmay be the solvent or diluent and the propionitrile, which is the onlyvolatile by-product formed. The 1,4-dicyanobutenes and/or adiponitrileare thereafter separated off by distillation in vacuo. The catalyst maybe separated from the reaction mixture by any known method, and may berecycled.

The following Examples illustrate the invention and show the effects ofvarying dilTerent factors individually or jointly.

EXAMPLE 1 The following are charged into a 125 cm stainless steelautoclave:

16 g (0.3 mole) of acrylonitrile stabilized by a 1/ 1000 part by weightof hydroquinone,

0.2 g of ruthenium trichloride, and

30 cm of methoxyethanol.

An initial hydrogen pressure of 40 bars is set up and the mixture thenheated to 1 C. for 16 hours, after which the reaction mixture isdistilled at normal pressure and l g of unreacted acrylonitrile,propionitrile, and 28 cm of methoxyethanol are removed between 76 and120 C. The remainder of the reaction mixture is then distilled in vacuoand there are obtained 7.4 g of a fraction of b.p. 97 to 108C, n,,1,4646, consisting principally of a mixture of cis 1,4- dicyanobutene-land trans 1,4-dicyanobutene-l, together with a little adiponitrile (3percent). The yield is 49.3 percent of theory relative to theacrylonitrile consumed. Hydrogenation of these dimers at normal pressureand temperature, in the presence of palladium on charcoal and in amethanol medium, quantitatively yields adiponitrile which on hydrolysisis converted to adipic acid melting at 150 to 151 C., with a yield of 97percent relative to the theoretical yield.

On repeating the same experiment but without using hydrogen, nodimerization product is obtained. The same negative result is obtainedif nitrogen is used in place of hydrogen, the initial pressure againbeing 40 bars.

EXAMPLE 2 On repeating the experiment of Example 1 but working withacrylonitrile stabilized with 0.005 percent by weight of ammonia, thesame result is obtained as in Example 1.

EXAMPLES 3 TO 9 Working under the conditions of Example 1, with the sameamounts of reagents, but with the methoxyethanol in each case replacedby a different solvent, the following results are obtained:

16 g of acrylonitrile stabilized by a l/1000 part by weight ofhydroquinone, 0.48 g of ruthenium triiodide and 30 cm of methoxyethanolare charged into a 125 cm stainless steel autoclave, a hydrogen pressureof 40 bars is then set up, and the mixture heated to C. for 6 hours.After the treatment described in Example 1, 4.9 g of 1,4-dicyanobuteneare obtained, representing a yield of 48 percent of theory relative tothe acrylonitrile consumed.

EXAMPLE 1 l 160 g of acrylonitrile, 0.08 g of hydroquinone and 0.8 g ofruthenium acetylacetonate are charged into a 500 cm autoclave. Aninitial hydrogen pressure of 40 bars is set up and the mixture heated to1 10 C. for 6 hours, the hydrogen pressure being readjusted to itsinitial value whenever it falls to 20 bars. When the absorption ofhydrogen has ended, the mixture is cooled, the gas released from theautoclave, and the volatile fractions, consisting mainly ofpropionitrile, are removed by concentration under a vacuum from a waterpump. The mixture which has thus been concentrated is then distilled invacuo and 76.4 g of a fraction of b.p. 1 11 to C. are collected, thisbeing chromatographically pure adiponitrile. The distillation residuewhich contains the catalyst may be directly used for a further reaction.

When the same experiment is carried out in the presence of unstabilizeddistilled acrylonitrile, it leads to the fonnation of a practicallyequal amount of adiponitrile. The same is true in the case of commercialacrylonitrile stabilized with 0.005 percent by weight of ammonia.

0n repeating the same experiment but replacing the hydrogen pressure bynitrogen pressure, no dimerization occurs.

EXAMPLES 12 TO 18 16 g of acrylonitrile stabilized with a 1/1000 part byweight of hydroquinone, 0.4 g of ruthenium acetylacetonate, 30 cm of anorganic solvent, and hydrogen up to a pressure of 40 bars, are chargedinto a cm stainless steel autoclave. Thereafter the mixture is heated to110 C. for 6 hours, hydrogen being replaced as in the previous example.There is thus obtained adiponitrile, as shown in Table 1 below.

TABLE I Ex. Solvent Adiponitrile l2 methoxyethanol 5.8 g EXAMPLE 29 i3cyclohexane 4.8 14 acetone 5.3 A mixture of:

15 benzene 5.6 l6 diehyleneglycoi 6.6 161.4 g ofacrylon trile stabilizedwith a dimethyl ether 5 H2000 part by weight of hydroquinone, and 17methanol 5.1 0.8 g of ruthenium acetylacetonate Pmpwmmle was heated at130 C. for 7 hours 30 minutes at a constant hydrogen pressure of bars.

When the reaction was over, there were obtained 10.8 g of i0 unconvertedacrylonitrile, 54.9 g of propionitrile and 89.3 g of EXAMPLES 19TO 24 amixture of 1,4-dicyanobutenes and adiponitrile containing The examplesgiven in the form of Tables ll and ill below 9% l weight oflr4'dlcyanobutenes; The overall y l show the yields of1,4-dicyanobutenes or adiponitrile or dlmtrlles Is 59 percent of theoryrelative to the acrylonitrile tures of these products which are obtainedwhen the working converted conditions are varied for a given catalyst.All the experiments EXAMPLE were carried out in an autoclave identicalto that of Example 1, using g of acrylonitrile stabilized with a 1/1000part by 16 g of acrylonitrile containing 0.02 g of hydroquinone, weightof hydroquinone in each experiment, and working at a 0.35 g of theruthenium chloride/butadiene complex of formuconstant hydrogen pressurethroughout a given experiment. 20 l R Cl C H and 30 cm of methoxyethanolare charged TABLE II Catalyst: ruthenium neetylzieetonate (0.4 g

Total yield Dimers obtained relative to Temperathe A.N. Duration ture.pressure DC B A l N converted, Ex. (hours) C. (bars) (g.) (1.1.) percentNOTE.-DCB=l,4-dicyanobutene; ADN=arliponitrile: A.N.=a -rylonitrile.

TABLE III Catalyst: ruthenium stearate Total yield Dimers obtainedrelative to u Tempera' the A.N. stearate 1 Duration ture, pressure DCBADN converted, Ex. (g.) (hours) C. (bars) (g.) (g.) percent 1 Theruthenium sttornto was prepared by reaction of ruthenium trichloridewith sodium stcau'nto.

EXAMPLES 25 TO 27 An identical autoclave to that of Example 1 is chargedwith 40 g of acrylonitrile containing 0.02 g of hydroquinone and thecatalyst, followed by hydrogen up to a pressure of 40 bars, and isheated at 1 10 C. for 6 hours, the pressure being returned to itsinitial value when it falls to 20 bars. After carrying out theseparation treatments described above, the results given in Table IVbelow are obtained.

TABLE IV Ruthenium derivative used Product obtained Ex. (amount in g)ADN (g) DCB (g) 25 trichloride 0.4 14.2 3.5

26 methylacetylacetonate 0.4 16.9

27 acetylacetonate 0.4 20.4

the ruthenium methylacetylacetonate was prepared by reaction ofmethylacetylacetone with ruthenium trichloride at pH 7.

EXAMPLE 28 into a 125 cm stainless steel autoclave, an initial hydrogenpressure of 40 bars is then set up, and the mixture thereafter heated at110 C. for 6 hours. The final pressure is about 8 bars. 3.01 g ofunconverted acrylonitrile and 6 g of 1,4- dicyanobutene-l (b.p. 89 to102) are recovered from the reaction mixture by distillation. Yield:46.2 percent of theory relative to the acrylonitrile converted.

The complex used as the catalyst was prepared by the method of LYDON andcollaborators, Proceedings of Chem. Soc. p. 421 (December 1964), byheating ruthenium chloride (Ru CI;,) to C. with butadiene in2-methoxy-ethanol.

EXAMPLE 31 A mixture consisting of 32 g of acrylonitrile stabilized withhydroquinone and 0.2 g of the ruthenium complex used in the precedingExample was heated to C. for 23 hours, the heating being carried outunder a hydrogen pressure of 40 bars which is kept constant. Under theseconditions 12.4 g of chromatographically pure adiponitrile are obtained,which is a yield of 38 percent relative to the acrylonitrile converted.

EXAMPLES 32 TO 36 A mixture consisting of 40 g of acrylonitrilestabilized with hydroquinone and 0.200 g of dichlorotetrakis(acrylonitrile) ruthenium-ll is heated in an atmosphere of hydrogen,either without replacing the hydrogen consumed (experiment 32) or withthe hydrogen being recharged so as to maintain a practically constantpressure (experiments 33 to 36). At the end of the reaction theunconverted acrylonitrile and the desired dinitriles are separated byworking as in the preceding examples. The following Table V, which showsthe working conditions for each experiment, indicates the resultsobtained.

30 cm of 2-methoxyethanol, hydrogen was then introduced up to a pressureof 40 bars and the mixture heated for 6 hours at 110 C. When thereaction had ceased the mixture was treated as described in the preced-The dichlorotetrakis(acrylonitrile)ruthenium-ll used as the catalyst wasprepared by heating a mixture consisting of 64 g of acrylonitrile(containing 0.08 g of hydroquinone) and 4 g of ruthenium trichloridedissolved in 80 cm of methoxyethanol under reflux for 28 hours in anatmosphere of nitrogen, followed by filtration of the unreactedruthenium trichloride and concentration of the filtrate in vacuo.

EXAMPLES 37 TO 46 ing example, and 3.5 g ofa mixture consisting of 80percent of 1,4-dicyanobutenes and 20 percent of adiponitrile, (thepercentages being by weight) was obtained.

The bis( acrylonitrile )ruthenium dicarbonyl was obtained by reaction ofacrylonitrile with [Ru(CO under reflux for EA hours.

We claim:

1. A process for converting acrylonitrile to its straight chain lineardi-cyano dimer or its straight chain linear di-cyano hydrodimer whichcomprises dimerizing acrylonitrile in the presence of molecular hydrogenat a temperature of 50 to 150 C. under a hydrogen pressure of 1 to 50bars and in the presence of a ruthenium compound as catalyst.

2. A process according to claim 1 wherein the catalyst is a memberselected from the group consisting of the ruthenium salts of mineral andorganic acids.

1!; pressure Dimcrs obtained Experiments Stabiliscd without Proportionby acrylo- Maintained replacement; Total weight Total Weight nitrileSolvent Duration constant initial prcsweight yield, Ex. Catalyst, nature(g.) (g.) (cmfl) (hours) (bars) sure (bars) in g. DCB ADN percent 37.RuCL-KCIItCNM U. 300 40 16 6. 6 100 0 56 38 1(uCl;(C1I.-,CN):; 0. 300 161 (i 1 7 100 0 30 RLIC13(CII:,CHQCN)3" 0.200 16 30 fi 40 6.2 90 10 47I{UC1I5(C]I3CII2CN)3 (J. 200 40 O lfi 1f) 12. l) 90 10 RuCMCoIhCNh U.200 16 0 t; 40 6. 8 15 42 RUC12(C5I15N)11 0. 200 10 0 ti 40 5. 5 85 1534 I I r kuzcllcsndcmshl L, 0.140 16 1 r. 40 1.6 85 15 51 44"".[RuCMCgHnHn 0. 200 40 0 6 40 (1.6 10 57 45. RuCl;1(C;Ii5S-C2Ii5)t 0. 4770 0 6 30 19 66 33 00 46... RuC12(Cg11l7)-biS- 0.196 40 0 1, 40 14 90 1057 p-toluidine d 1 Methoxyethanol.

B Prepared according to the method described in .7. Chem. Soc. 2627(1964).

EXAMPLE 47 mal pressure to yield 9.7 g of acrylonitrile and 2.7 g ofpropionitrile, and subsequently in vacuo to yield 2.9 g of 1,4dicyanobutenes, the yield of dimers being 46 percent of theory relativeto the acrylonitrile converted.

The diodotetrakis(acrylonitrile)ruthenium was prepared in a similarmanner to the dichlorotetrakis( acrylonitrile)ruthenium but usingruthenium iodide.

EXAMPLE 48 A cm autoclave was charged with: 16 g of stabilizedacrylonitrile, 0.25 g of bis(acrylonitrile)ruthenium dicarbonyl, and

3. A process for the preparation from acrylonitrile of a member selectedfrom the group consisting of 1,4-dicyanobutene, adiponitrile andmixtures thereof, comprising heating acrylonitrile to a temperature of50 to C. under a hydrogen pressure of 1,to 50 bars in the presence of,as catalyst, a ruthenium catalyst selected from the group consisting ofruthenium halides, complexes formed between a ruthenium halide and anelectron donor, ruthenium chelate complexes and ruthenium salts of fattyacids.

4. A process as claimed in claim 3 wherein the catalyst is a rutheniumcatalyst selected from the group consisting of a ruthenium halide,thiocyanate, sulphate, nitrate, oxyhalide, hydroxyhalide, acetate,oxalate, stearate, naphthenate, alcoholate, phenate, and alkali andalkaline earth ruthenates,

halogenoruthenates of sodium and potassium nitrosochlororuthenium,trichlororuthenium hexamine, ruthenium acetylacetanate,3-bromo-2-4-pentadionatoruthenium (lll), 1,1,l-trifluoro2,4-pentadionateruthenium (Ill), ruthenium glyoximate, quinolinate, andsalicylaldehydate, and ruthenium derivatives of ethylene diamine, a,a'dipyridyl and o-phenanthroline, and complexes of ruthenium 5. A processfor the preparation from acrylonitrile of a member selected from thegroup consisting of 1,4-dicyanobutene and/or adiponitrile whichcomprises heating at to C. acrylonitrile under a hydrogen pressure of 5to 40 bars in the presence of, as catalyst, a member selected from thegroup consisting of mineral and organic ruthenium derivatives.

2. A process according to claim 1 wherein the catalyst is a memberselected from the group consisting of the ruthenium salts of mineral andorganic acids.
 3. A process for the preparation from acrylonitrile of amember selected from the group consisting of 1,4-dicyanobutene,adiponitrile and mixtures thereof, comprising heating acrylonitrile to atemperature of 50* to 150* C. under a hydrogen pressure of 1 to 50 barsin the presence of, as catalyst, a ruthenium catalyst selected from thegroup consisting of ruthenium halides, complexes formed between aruthenium halide and an electron donor, ruthenium chelate complexes andruthenium salts of fatty acids.
 4. A process as claimed in claim 3wherein the catalyst is a ruthenium catalyst selected from the groupconsisting of a ruthenium halide, thiocyanate, sulphate, nitrate,oxyhalide, hydroxyhalide, acetate, oxalate, stearate, naphthenate,alcoholate, phenate, and alkali and alkaline earth ruthenates,halogenoruthenates of sodium and potassium, nitrosochlororuthenium,trichlororuthenium hexamine, ruthenium acetylacetanate,3-bromo-2-4-pentadionatoruthenium (III), 1,1,1-trifluoro2,4-pentadionateruthenium (III), ruthenium glyoximate, quinolinate, andsalicylaldehydate, and ruthenium derivatives of ethylene diamine, Alpha, Alpha '' dipyridyl and o-phenanthroline, and complexes of rutheniumderivatives wherein the ruthenium derivatives are halogenatedcarbonylated or nitrosylated ruthenium derivatives, with electrondonating agents having lone electron pairs, said agents selected fromthe group consisting of phosphines, arsines, stibines, and amines, andcomplexes obtained by reacting ruthenium halides and hydridohalides withaliphatic and cycloaliphatic monoolefines and diolefines, acrylic andmethacrylic derivatives, saturated and unsaturated aliphatic,cycloaliphatic, and aromatic nitriles and dinitriles, and aromatic andaliphatic isonitriles.
 5. A process for the preparation fromacrylonitrile of a member selected from the group consisting of1,4-dicyanobutene and/or adiponitrile which comprises heating at 100* to130* C. acrylonitrile under a hydrogen pressure of 5 to 40 bars in thepresence of, as catalyst, a member selected from the group consisting ofmineral and organic ruthenium derivatives.